Prediction and monitoring of treatment effect using T1-weighted dynamic contrast-enhanced magnetic resonance imaging in colorectal liver metastases: potential of whole tumour ROI and selective ROI analysis.

PURPOSE

To evaluate dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for prediction and early monitoring of treatment in colorectal liver metastases.

MATERIALS AND METHODS

Ten patients were included. Baseline and follow-up DCE-MRI examinations were evaluated by whole tumour and selected ROI placements calculating Kep-values. Selective ROIs, concentric-like and hot spot, were drawn on early arterial phase images. Monitoring of treatment was performed comparing RECIST1.1 criteria with whole tumour and selected ROI placement. To evaluate treatment effect between responders and non-responders, independent samples t-test was used on Kep-values.

RESULTS

In each patient largest lesion was evaluated totalling 10 target lesions. At baseline, for whole tumour ROI placements mean Kep-values in responders were significantly higher than mean Kep-values in non-responders (t=7.481, p<0.001). Selective ROI placement comparison of mean Kep-values at baseline and after 6 weeks of treatment (first follow-up measurement) showed significant decrease in responding patients (t=4.706, p=0.003) whereas increase in Kep-values in non-responding patients was not statistically significant.

CONCLUSION

This preliminary study shows that baseline Kep for whole tumour ROI is a predictor for treatment outcome. Decrease of Kep using selective ROIs allows early identification of response after 6 weeks of treatment.